Furnace seal



March 10, 1942. R, PURSEL 7 2,275,652

FURNACE SEAL.

Filed July 5, 1940 4 Sheets-Sheet 2 5&5

INVENT OR. HA FOL D E. PUPSEL March 10, 1942. H. R. PURSEL 2,275,652

FURNACE SEAL Filed July 5, 1940 4 Sheets -Sheet 3 INVENTOR. HA Z01 D k. PUESEL A TTOPNEYS.

March 10, 1942. PURSEL 2,275,652

FURNACE S EAL Filed July 5, 1940 4 Sheets-Sheet 4 INVENTOR. HAROLD ,Q. PURSEL BY W ATTORNEYS.

furnaces.

Patented 1c, 1942 Harold B. Purse], Philadelphia, Pa assignor' to The AliemShermanaHofl Company, Philadeb plain, Pm, a corporation of Pennsylvania Application July 5, 1940, Serial No. 343,934

Claims.

This invention relates to steam boiler furnace structures or the like and more particularly to sealing means for closing an open joint between the furnace bottom and an ash hopper or receiving vessel disposed below the furnace outlet,

which sealing means will efl'ectively prevent the infiltration of air into the furnace while permitting the necessary relative expansion and contraction of the parts.

l The tendency in modern boiler practice is toward the employment of much greater draft than has previously been used. Certain modern furnaces have a draft as high as 2" of water as distinguished from .1" to .15 which was usual in the older types of furnaces. With the low draft values previously employed sliding seal structures of various types were employed between the furnace bottom and the ash hopper disposed therebelow and with the low draft furnaces infiltration of air through such sliding seal arrangements was However, in the modern high draft furnaces, the old type sliding seal permits excessively large quantities of air to be drawn into the furnace between the sliding joints with resulting substantial reduction in furnace emciency.

It is among the objects of the present invention to provide a furnace seal which will effectively and positively prevent infiltration of air between the furnace bottom and the ash hopper while permitting expansion and contraction of the furnace walls in any direction and in any degree encountered in practice, Qther objects of my invention include the provision of a water seal for furnace bottoms which is protected from the radiant heat from the furnace interior and which will remain completely effective regardless of uneven expansion of the furnace walls in different directions; the provision of a water seal for furnace bottoms whicltis simple in form, may readily be inspected and repaired or replaced when necessary, and which will permit dewatering of the ash hopper while maintaining the seal; and the provision of a furnace seal structure which may readily be adapted to various types of The above and other objects of my invention will appear from the following description of several embodiments thereof, reference being had to the accompanying drawings, in which- Figure 1 is a horizontal cross-sectional view of a furnace bottom incorporating my invention, taken substantially on line l-i' of Figure 2.

Figure 2 is a vertical cross-sectional view of the furnace bottom and ash hopper shown in not particularly serious.-

Figure 1 taken on line 1-2 of Figure 1 and illu strating one form of my water seal structure.

Figure 3 is a transverse cross-sectional view taken on line 3-3 of Figure 1.

Figure 4 is an enlarged fragmentary vertical cross-sectional view of my water seal arrangement taken on line 4-4 of Figure 1.

Figure 5 is a view generally similar to Figure 4 but taken on line 5-5 of Figure 1 and showing the water inlet and outlet connections to the seal trough.

Figure 6 is an enlarged fragmentary horizontal cross-sectional view taken at the corner of the furnace bottom shown in Figures 1 and 2 and illustrating the flexible sealing connections between the seal plates.

Figure 7 is a vertical cross-sectional view of the corner seal construction taken on line l--l of Figure 6.

Figure 8 is a vertical cross-sectional view of another form of furnace bottom in which the furnace outlet is circular in form and the seal is correspondingly circular.

Figure 9 is a vertical cross-sectional view of a modified forth of my invention associated with a furnace having water cooled walls supplied with lower headers.

Figure 10 is a fragmentary plan view of the apparatus of Figure 9 taken on line ill-i0 of Figure 9. a

Figure 11 is a partial end view from the right of Figure 9.

The furnace bottom shown in Figures 1, 2 and 3 is rectangular in form and includes side walls 5 and 2 and end walls 53 and t. The outlet defined by these walls conveys the products of combustion from the furnace into the ash hopper situated therehelow. 'This hopper has sloping end walls 5 and '6 and side walls having vertical portions 1 and t which join sloping portions 9 and iii. A grid i I may be disposed in the hopper and suitable means, not shown, maybe provided for maintaining a water level at l 2 in the hopper. The products of combustion fall into the water in the hopper and are removed through the pipe i3 by the pump H for conveyance to any suitable place of disposal.

The upper edges of the hopper walls are spaced from'the lower edges of the furnace walls to per mit relative vertical movement thereof due to contraction and expansion of the furnace structure during operation. Furthermore, the hopper walls are disposed outside of the furnace walls and spaced therefrom to permit lateral and endwise expansion of the furnace walls. This con 'struction,

cie' rlyiseen in Figures 2 and 3, leaves a subs't I pace between the furnace walls and the hoppe walls throughout their entire perimeter and in order to seal this gap and prevent infiltration of air therethrough I- pro-- vide a water seal comprising a trough T extend: ing entirely around the hopper structure and outlet opening 26. A circular fln supported on projecting flanges or projections 13 i which form a part of the supporting structure for the hopper walls. ,The trough T is preferably endless and is open at its top to permit the entry of the sealing flns l6 which are secured to downwardly projecting webs l1 by boltsl8. Leakage around the top of webs I1 is prevented by welding or otherwise securing the top of the webs to the bottom structural members of the furnace walls,as seen in Figures 4, 5 and 7. Suitablegaskets webs l1 and the flns I9 are preferably employed between the 16 to form leak-proof joints therebetween. The fins l6 extend down into the trough T which is provided with a plurality of water inlet pipes 20having control valves 20' for regulating the flow-of water therethrough and overflow outlet pipes 2| extending into the interior of the hopper. The fins i6 are of such length that they will always project into the body of water in the trough pansion or contraction of the furnace bottom or movement thereof up and down relative to the hopper, a positive seal will be maintained at all times between the hopper and the furnace bottom.

At the corners of the rectangular furnace bottom illustrated in Figures 1 and 2 the seal plates l6, which are co-extensive with the furnace walls,

are spaced apart and connected by bers 22 which are secured to the sealing fins and webs l6 and I! in a leak-proof manner by screws '23 and binding strips 24. The flexible members into abutting relation with the projecting flange 25 of the furnace bottom frame structure (see Fig.7).

It will be observed-that the flexible fabric corner joints of my sealing fins permit the inevitably unequal expansion of the furnace walls in different directions to take place without any strain or load being imposed upon the parts.

Furthermore, they maintain an efiective seal substantially preventing infiltration of the air at the corners.

Referring particularly to Figures 4 and 5, it will be observed that the trough T is disposed entirely outside of the walls of the ash hopper and is effectively protected from radiant heat from within the furnace bottomby the hopper walls themselves. I

It is noted that the water level on the inside of thesealing fins i6 is shown as higher than that on the outside and it will be understood that this represents the operating condition of the furnace, the water level difference being due to the reduced pressure existing inside of the furnace structure.

T and, regardless, of exbottom of the fins It; up

Although the overflow from the trough T is illustrated as being conducted through pipes 2| into the hopper, it will be unproviding suitable overflow pipes from the outer wall of the trough T.

In-Figure 8 I have illustrated my furnace seal as applied to a furnace bottom having a circular 2!. is secured to the furnace bottom, as by welding at 28, and

projects down the annular trough 23 supported on the hopper top 30. An inlet pipe 31,; equipped with a suitable control valve 32, sup

plies water to the trough 23 and the overflow is directly over the lip ortne upwardly projecting inlet wall 33 of the hopper or ash receiving chamber 3|. Thus, the overflow of water from the trough '29 in this arrangement will cool the nose of the hopper and protect the refractory materialfrom excessive heat. With this arrangement a 'perfectseal is maintained at all times between the-parts and the trough water performs the dual function of maintaining the seal and cooling the entering throat of the ash receivfined by the headers 36, 31 and 38. Seal plates 33 and 40 are secured to and supported by the transverse headers 36 and 38 and seal plates ll are supported by the headers 31.- (Only one header 31 is shown inthe drawings butit'will be understood that another similar header may be disposed directly opposite the header 31 shown in Figure 9.) The plates ll extend around the comer indicated at 42 and, as is seen at 43 in Figure 11, end approximately in line with the inner edge of the header 31. Space is, of course, provided between the ends of the headers 36 and 38 and the sides of the headers-31 and a gap occurs between the ends of the seal plates 39 and Ill and the angle extensions 43 of the seal plates 4|. These gaps are closed by flexible connecting members 44, preferably made of impervious fabric.

The ash collecting hopper walls are disposed below the headers 36,31 and 38 and, as illustrated, include spaced inner -and outer double walls 45 and 46. These walls extend from the bottom 41 of the hopper to the top thereof and perform the dual function of providing a trough into which the seal plates 39 and 40 extend and forming water cooled walls for the hopper. Re-

walls through the pipes 56 and 55 and overflow from the trough occurs through suitably located pipes56. At'the bottom of the water cooled walls I a drain pipe 51, controlled by a valve 58, permits complete emptying of the trough when desired.

It will be understood that the drawings illustrating the various embodiments of my invention are somewhat diagrammatic and that in actual furnace constructions numerous details would be included which are not shown as they do notpertain to .the present invention; Where the term furnace bottom is used in the speciflcation and claims it is intended to mean either the furnace walls as shown inFigures l to 8 inclusive, the bottom headers of water cooled walls as shown in Figures 9, and 11, or other parts of the furnace structure adjacent the bottom outlet thereof to which the sealing flanges are attached to complete a water seal with the trough associated with the hopper disposed below the furnace outlet. 2

Although I have described the illustrated forms of my improved furnace seal in considerable detail it will be understood by those skilled in the art that my invention is readilyadaptable to other types and shapes of furnace bottom outlets and modifications may be made in the arrangement and form of the parts without departing from the spirit of my invention. I do not, therefore, wish to be limited to the specific embodiments herein disclosed but claim as my invention' all forms thereof coming within the scope of the appended claims.

I claim:

1. In a seal for the joint between a furnace bottom and a hopper disposed therebelow, a trough supported by said hopper, a plurality of fin members secured in air-tight contact to said furnace bottom and extending into said trough, the adjacent ends of said fin members being spaced apart to permit relative movement thereof, a flexible, substantially impervious member connecting said fin ends and extending into said trough, and means for maintaining a body of water in said trough above the bottom edge of said fins and flexible member.

2. In a combination, a furnace bottom having a generally rectangular outlet opening, downwardly projecting fins supported in air-tight contact on the furnace outside of and adjacent said. outlet, the ends of said fins being spaced at the corners of said rectangular opening, flexible, air impervious material connecting the adjacent ends of said fins at said corners, a hopper below said outlet, a trough supporter by said hopper below said fins, said flns and flexible corner connections extending down into said trough, and means for supplying water to said trough to form a seal.

meeting said spaced ends.

tom in air-tight contact therewith and extend-' ing into said trough, and means for supplying waterto said trough, said fin means including a plurality of seal plates having spaced ends and flexible, substantially impervious portions con- 4. In combination, a furnace structure having a bottom outlet opening and downwardly projecting'fins extending around said opening and having air-tight contact with said furnacestructure, a hopper below said outlet opening having spaced inner and outer walls forming an open topped double wall structure extending around and below said outlet opening, said fins extending into the space between said walls, and means for maintaining water in said space at a level above the bottom edge of said fins, said fins including spaced rigid sections connected by flexible substantially impervious sections.'

5. In combination with a steam generating.furnace having walls defining an ash discharge opening, a hopper below said ash discharge opening and having a top opening to receive ash from said furnace,- a receptacle for water surrounding Y the hopper adjacent to said top opening and having substantially air-tight contact with said hopper, a plurality of separate fin means secured in substantially air-tight connection to' said fur-, nace around the outside of said ash discharge opening, said 'fin means projecting into said water receptacle between the side walls thereof, flexible, gas impervious means connecting adjacent ends of said fin means, and means to maintain a level .of water in said receptacle above the bottom' of said fin means.

- .HAROLD I R. PURSEL. 

